Oscillation circuits that use crystal oscillators are widely used in the art in applications such as timepieces and portable telephones and computer terminals. In such portable devices, it is necessary to design them to reduce power consumption and thus have longer battery lives.
From the viewpoint of reducing power consumption, the present inventors have analyzed the power consumptions of semiconductor devices that are installed in the electronic circuitry used in portable electronic equipment, particularly wristwatches. The results of this analysis show that the power consumption of the oscillation circuit parts of such a semiconductor device is far larger than that of the other circuits. In other words, the present inventors have discovered that reducing the power consumption of the oscillation circuit parts used in portable electronic equipment is effective for increasing battery life.